The average monthly expenditure of a family was ₹18,600 during the first three months, ₹21,750 during the next four months and ₹22,840 during the last five months of a year. If the total savings during the year was ₹1,43,020, then the average monthly income(in ₹) of the family was:

33,335

Sum of expenditure of first 3 months = 3 × 18600 = 55800

Sum of expenditure of next 4 months = 4 × 21750 = 87000

Sum of expenditure of last 5 months = 5 × 22840 = 114200

Savings = 143020

Average monthly income = \(\frac{55800 + 87000 + 114200 + 143020  }{12}\)

= \(\frac{400020}{12}\)

= 33335